Background: Poultry products are the highest-risk foods for containing antibiotic-resistant and extraintestinal-pathogenic E. coli. Whether such strains or their resistance elements are actually transmitted to consumers and, if so, pose a significant human health threat, is unknown. Goals: Assess poultry contact and consumption as risk factors for human colonization with trimethoprim-sulfamethoxazole (TS)-, fluoroquinolone (FQ)-, and extended-spectrum cephalosporin (ESC)-resistant E. coli (i.e. TSREC, FQREC, and ESCREC), and define the degree of commonality among poultry-source versus human-source TSREC, FQREC, and ESCREC and their respective resistance elements. Plans: Temporally-matched TSREC, FQREC, and ESCREC isolates from fecal samples from 629 human volunteers in four rural Midwestem communities, 160 retail poultry items fi'om the same locales, and local clinical microbiology laboratories will be compared. Risk factor analysis wi.ll identify epidemiological predictors of human colonization with TSREC, FQREC, and ESCREC, including contact with and consumption of poultry. Detailed molecular analysis will define the relationships between poultry-source and human-source isolates and their respective resistance elements, plus clarify the virulence potential for humans of poultry-source E. coll. Relevance to the RFA: The proposal addresses Research Objective II of the RFA by helping implement Action Item #50 found in "A Public Health Action Plan to Prevent Antimic_:obial Resistance (Part I: Domestic Issues): Focus Area II, Prevention and Control": Conduct additional research to further define the effects of using various veterinary drugs on the emergence of resistant bacteria that infect or colonize food animals of different species, using various animal husbandry practices [indiirectly addressed]. Identify risk factors and preventive measures [addressed, for transmission to humans]. Assess the associated risk of. " Transmission of AR infections to humans [addressed]," Clinical disease in humans [addressed],' and Transfer of resistance factors from animal flora to human flora [addressed]. Does the research address a current and compelling problem of antimicrobial resistance that is of high public health importance and for which research is needed? [yes].